Debugging a program located in internal FLASH of the M52235 ColdFire MCU.

[Claude Sylvain]

Hello Mark,


 >>
 >>Claude Sylvain wrote:
 >>
 >>
 >> 1) Get the startup source code and try to patch those problems.  The
 >> startup source code is not included with Sourcery G++ Lite.
 >> Is it possible to get it ?
 >>

 >
 > Mark Mitchell wrote:
 >
 > All of the source code is available in the source package.  The crt0
 > code is also available in m68k-elf/lib/cf-crt0.S of the binary
 > installation, although this file does not include __reset.  (This code
 > is not covered by the GPL, so there is no requirement that it be
 > provided at all, but our packaging machinery will automatically include
 > it, as a convenience to users.)
 >
 > Sourcery G++ Lite 4.1-32 does appear to have a defect in the handling of
 > __reset for unhosted mode.  Our Personal and Professional edition
 > customers already have this fix; a future Lite edition release will
 > correct it as well.
 >
 > However, even with 4.1-32, you may simply define your own __reset
 > function (in assembly code) and link it into your program.  It will take
 > precedence over the version in the library.
 >

I wrote my own startup module (crt0_flash.S).
In this startup module, I put the "new" code associated with __reset 
and __start.

In the linker script file, I replaced all the reference to the 
original startup object file (cf-unhosted-crt0.o) by the one I wrote 
(crt0_flash.o).

Sadly, when I build the application, the linker seems to see multiple 
definition of __reset and __start !?
This tell me that __reset and __start are not defined in 
cf-unhosted-crt0.o module, but elsewhere in another library.  This 
also tell that linker do not handle multiple definition of __reset 
and __start symbols.

Here is the makefile output:

				   ----------

c_mcf52235>make
m68k-elf-as -mcpu=52235 --gstabs -al -o ./obj/isv_flash.o
\
./src/isv_flash.S > ./obj/isv_flash.lst
m68k-elf-as -mcpu=52235 --gstabs -al -o ./obj/crt0_flash.o
\
./src/crt0_flash.S > ./obj/crt0_flash.lst
m68k-elf-gcc -c -I./src -I./src/common -I./src/drivers -mcpu=52235 
-T./src/m5223
5evb-flash.ld -g -o ./obj/main.o ./src/main.c
m68k-elf-gcc -c -I./src -I./src/common -I./src/drivers -mcpu=52235 
-T./src/m5223
5evb-flash.ld -g -o ./obj/common.o              \
./src/common.c
m68k-elf-gcc -c -I./src -I./src/common -I./src/drivers -mcpu=52235 
-T./src/m5223
5evb-flash.ld -g -o ./obj/uart0.o               \
./src/drivers/uart0.c
m68k-elf-gcc -c -I./src -I./src/common -I./src/drivers -mcpu=52235 
-T./src/m5223
5evb-flash.ld -g -o ./obj/ach_con.o     \
./src/common/ach_con.c
m68k-elf-gcc -I./src -I./src/common -I./src/drivers -mcpu=52235 
-T./src/m52235ev
b-flash.ld -g -o ./out/basic_mcf52235.elf ./obj/isv_flash.o 
./obj/crt0_flash.o .
/obj/main.o ./obj/common.o ./obj/uart0.o ./obj/ach_con.o
./obj/crt0_flash.o:./src/crt0_flash.S:50: multiple definition of `__start'
./obj/crt0_flash.o:./src/crt0_flash.S:50: first defined here
./obj/crt0_flash.o:./src/crt0_flash.S:32: multiple definition of `__reset'
./obj/crt0_flash.o:./src/crt0_flash.S:32: first defined here
collect2: ld returned 1 exit status
make: *** [out/basic_mcf52235] Error 1

C:\Documents and Settings\Claude Sylvain\My 
Documents\Code\coldfire-gnu\prj\basi
c_mcf52235>

				   ----------


So, It seems impossible to make my own startup module.

I think, it will be better for me to wait the next release of 
Sourcery G++, or try to convince my boss to buy a Sourcery G++ 
licence (not sure I will succeed, since we only evaluate the tool for 
future project(s)).


Thank you Mark for your help.

Also, thank you to Marc Vincent for its __reset code example and advices.


Claude Sylvain
Electro-Technica inc.